%! TEX root = /Users/luigipertoldi/LaTex/test-proj/main.tex
\begin{equation}
i\mathcal{M}=iG^2_FV^2_{ud}[\bar{u}(p_1)\gamma^\mu(1-\gamma_5)v(q_1)][\bar{u}(p_2)\gamma^\nu(1-\gamma_5)v(q_2)]J_{\mu\nu}-(p_1\leftrightarrow p_2)
\end{equation}
